The present invention relates to a structure for preventing a leak at a synthetic resin tube joint.
Various types of liquid chemicals and water are frequently used in a process of manufacturing semiconductor devices, displays, etc. The various types of liquid chemicals include, for example, an acidic solution, such as hydrofluoric acid, sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, etc., an alkaline solution which contains potassium hydroxide, sodium hydroxide, ammonium, etc., chemicals used in cleaning solutions, etc. Of the liquid chemicals, ozonized dilute hydrofluoric acid is used in a process of cleaning and etching semiconductor substrates, etc.
Such liquid chemicals are transferred through a transfer system including a tube or pipe for which a synthetic resin tube made of a fluoro-based resin is generally used. Since the chemicals flowing through a synthetic resin tube employed in transfer systems of semiconductor manufacturing facilities are high-purity and deadly poisonous chemicals, a leak of the chemicals may be fatal not only to a production yield rate of semiconductor products but also to humans. Accordingly, stricter and tighter sealability is required for a plurality of synthetic resin tubes that form a transfer system and unions, nuts, connectors, valves, and the like for connecting, opening and closing the synthetic resin tubes.